| Zeotap | Berlin |
| Zeppelin Lab GmbH | |
| Zeppelin Universität | |
| Zeppelin Universität gemeinnützige GmbH | |
| zero360 GmbH | |
| Zerovision | Berlin |
| Zertificon Solutions GmbH | Berlin |
| Zertisa GmbH | Bavaria |
| Zeryezzer Design München | Bavaria |
| ZES ZIMMER Electronic Systems GmbH | Hesse |
| Zeta Software GmbH | Baden-Württemberg |
| Zeta Test Management | Baden-Württemberg |
| Zetaguard | Berlin |
| ZetCom | North Rhine-Westphalia |
| Zetmedia Marketing-Support | North Rhine-Westphalia |
| ZETTLER Electronics GmbH | Bavaria |
| ZetVisions AG | Baden-Württemberg |
| ZeyOS GmbH & Co. KG | Bavaria |
| ZF Friedrichshafen AG | Baden-Württemberg |
| Ziegle GmbH | |
| Ziegler Group | |
| Ziegler Systemhaus GmbH | Baden-Württemberg |
| ZIEHL Computersysteme | Baden-Württemberg |
| ZIEHL-ABEGG SE | |
| ZIEMER GmbH | Bavaria |
| Ziffer Consulting GmbH | |
| Zigzag GmbH | |
| Zikula | Berlin |
| Zimmer & Kreim GmbH & Co. KG | |
| Zimmermann Investment GmbH & Co. KG | |
| Zing Coach | Bavaria |
| Zinsler InfoSelect GmbH & Co. KG | Baden-Württemberg |
| Zipmend GmbH | |
| Zippo Zimmermann | Saarland |
| Ziraat Bank International AG | Hesse |
| Zirkel Technologies GmbH | |
| ZiWu-Soft EDV Systeme GmbH | Baden-Württemberg |
| ZMI GmbH | Bavaria |
| ZMS | Berlin |
| ZNET Group GmbH | Hesse |
| ZNS GmbH | |
| znt Management Holding GmbH | Bavaria |
| Zoi | Baden-Württemberg |
| Zoi TechCon GmbH | |
| Zolar GmbH | |
| Zöllner Büro- & IT-Systeme GmbH | Brandenburg |
| Zollner Elektronik AG | |
| zone35 GmbH & Co. KG | Berlin |
| zonezero GmbH | North Rhine-Westphalia |
| Zoom Internetagentur | Hesse |